The broad purpose of the proposed research program is to investigate the nature and neurological organization of the capacity for understanding natural language sentences. The research will focus on the interface between syntactic and conceptual representations. It will examine the real-time operations involved in combining lexical conceptual content into contextualized interpretations; and it will examine the effects of variously sited focal brain damage on these operations. One aim is to determine if combinatorial meaning the combination of word meanings in a sentence is directed not only by the syntactic arrangement of the words in that sentence, but also by non-syntactic, generative lexical operations. A second aim is to determine if these two kinds of combinatorial processes can be dissociated by brain damage. This work will use reaction-time paradigms as an on-line means of studying these sentence comprehension operations. This program of research should yield information of relevance to remediation in aphasia. It should specify the kinds of real-time processing limitations that therapeutic efforts must address.